1. Field of the Invention
The present invention relates to a dental and oralogic composition containing a photocatalytic titanium oxide, and to a method of forming a photocatalytic titanium oxide-containing film on the surface of a dental material in or not in the mouth. More preferably, the invention relates to a dental and oralogic composition containing a photocatalytic titanium oxide, which is to be applied to dental materials including tooth crown restorative materials, dentures, denture bases, denture rebases, orthodontic bases, wires, bridges, mouth pieces, etc., to teeth, gums or oral mucous membranes, or to teeth having been restored with composite resin or coated with dental manicure, to thereby form a film of the composition on their surfaces. The film thus formed prevents the formation of biofilm, that is, dental plaque containing a large number of bacteria in the mouth, and prevents dental caries and periodontitis or prevents the promotion of such dental diseases. In addition, it prevents or retards the discoloration of teeth and dental materials to be caused by adhesion of cigarette tar or food deposits thereto, bleaches discolored teeth, and even prevents halitosis. The invention also relates to a method of forming such a photocatalytic titanium oxide-containing film on the surface of a dental material in or not in the mouth.
2. Discussion of the Background
Oral diseases include dental caries, gingivitis, periodontitis and other periodontal diseases (pyorrhea alveolaris, etc.), stomatitis, etc. Of these, dental caries is one typical disease of teeth, and it is believed to be caused by intrabuccal microorganisms that produce acid, which dissolves the enamel of teeth. Above all, it is said that Streptococcus mutans is a typical pathogen that causes dental caries. It is also said that periodontitis, which is a disease of peridentium, is caused by intrabuccal bacteria. In order to prevent and cure such diseases, it is important to immediately remove the dental plaque of intrabuccal bacteria adhered to the surface of teeth.
Expectant treatment has heretofore been employed to prevent and cure for each of the above types of oral diseases. For example, to prevent dental caries, fluorine-containing compounds are applied to teeth, or antibacterial agents are incorporated into dental materials. At present, however, these are not always effective or satisfactory in dental treatment. To restore and treat decayed teeth, dental materials such as dental metal (metal inlay), dental resin (cement for dental use), dental porcelain (porcelain inlay), composite resin (composite plastics for dental use) and others are used with which decayed teeth are restored or prosthetically treated. However, it is said that dental plaque of bacteria is readily formed on the surf aces of these dental materials. On the other hand, tooth brushing, mechanical dental scaling, and local application of chemicals to teeth and therearound have heretofore been recommended for preventing and curing periodontitis and other periodontal diseases. However, these are troublesome and time-consuming, and it is difficult to say that their effect is satisfactory for preventing and curing the dental diseases.
The surfaces of teeth and dental materials are often discolored due to the adhesion of cigarette tar or food deposits thereto, but no one knows an effective means for preventing the discoloration and for removing the adhered cigarette tar or food deposits, and a solution to these problems is desirable. Oral diseases such as dental caries, gingivitis, periodontitis and other periodontal diseases (pyorrhea alveolaris, etc.) cause halitosis, and it is likewise desirable to establish an effective means for preventing and removing halitosis.
Recently, a coating material that contains a photocatalytic titanium oxide has been proposed. This coating material is applied to the surfaces of appliances, tiles glass articles and others to form thereon an antibacterial, antifogging, antisoiling or deodorizing film owing to the photocatalytic activity of the titanium oxide in the material.
A liquid coating composition for teeth is known for applying such a photocatalytic titanium oxide to dental materials, which composition is prepared by mixing a photocatalytic titanium oxide with methyl α-cyanoacrylate and a resin component such as polymethyl methacrylate or the like (JP-A-175923/1997.) The published specification discloses that dental caries can be prevented by coating teeth with the coating composition. However, methyl α-cyanoacrylate used in the coating composition is extremely rapidly polymerized and cured by the moisture in air or by water in the mouth. The coating composition must therefore be applied to teeth within an extremely short period of time, and the coating composition is handled only with difficulty. In addition, the coating composition may not be completely safe for dental use in the mouth, since the composition contains methyl α-cyanoacrylate. Another problem with the coating composition is that its adhesion durability to teeth is poor, and the film that results from the coating composition is often peeled from teeth.